Medical fluid infusion and aspiration

ABSTRACT

In an embodiment, a slit valve catheter has a generally tubular catheter body with an exterior surface exposed to an environment and an interior surface defining a lumen. The catheter further includes a valve which has a protuberance projecting radially from the catheter body.

FIELD OF THE INVENTION

[0001] This invention relates to medical fluid infusion and aspiration.

BACKGROUND OF THE INVENTION

[0002] Infusion of fluid into the body or aspiration of fluid from thebody is often performed with a catheter which is inserted beneath theskin. The catheter has a lumen through which fluid can flow. In somedesigns, the lumen is closed at the insertion end of the catheter andfluid communication between the body environment outside the catheterand the lumen is controlled by a slit through the catheter wall whichacts as a valve. The catheter has a hub on the end outside the bodywhich can be connected to a syringe for increasing and decreasing thepressure inside the lumen.

[0003] For infusion, the fluid pressure inside the lumen is increased toforce the catheter body adjacent the slit to flex outward, separatingthe opposing faces of the slit and forming an aperture through whichfluid may pass to the body environment. For aspiration, the pressureinside the lumen is decreased to force the catheter body adjacent theslit to collapse inward, forming an aperture through which fluid mayflow into the lumen. At neutral pressures, the catheter body assumes anunflexed condition in which the faces of the slit are opposed, whichforms a seal to prevent infusion or aspiration.

[0004] A valve can be made to permit infusion only, aspiration only, orboth infusion and aspiration. A valve that operates for infusion onlycan be formed by making the slit in a convex catheter wall portion,since the convex shape facilitates flexing outward while resistingflexing inward. A valve that operates for aspiration only can be formedby making the slit in a concave wall portion, which facilitates flexinginward while resisting flexing outward. A flat wall portion facilitatesflexing in either direction and can be used to form a two-directionvalve.

[0005] A two-direction valve may also be formed by chemical weakening ofthe catheter wall adjacent the slit, which facilitates flexing in bothdirections so that the valve works smoothly during infusion andaspiration. The lumen may also be shaped with a linear side thatterminates to form regions of reduced catheter wall thickness. Theregions act as hinges at which inward and outward flexing is enhancedand the area between the regions may have a greater wall thickness whichfacilitates sealing.

[0006] The catheter may also have multiple valves and multiple lumens.Further discussion of catheters is found, for example, in Groshong U.S.Pat. No. 4,549,879, Nichols U.S. Pat. No. 94,753,640, Lui U.S. Pat. No.5,261,885, and Luther U.S. Pat. No. 5,522,807 the entire contents of allof which are incorporated herein by reference.

SUMMARY OF THE INVENTION

[0007] In one aspect, the invention features a slit valve catheter withan elongated, generally tubular catheter body having an exterior surfaceexposed to an environment and an interior surface defining a lumen. Thecatheter further includes a valve which has a protuberance projectingfrom the catheter body and a slit through the protuberance and catheterbody. In another aspect, the invention features a slit valve catheterhaving an elongated, generally tubular catheter body with an exteriorsurface exposed to an environment and an interior surface defining alumen. The catheter further includes a valve with a generally convexexterior surface portion and a protuberance projecting radially outwardfrom the convex exterior surface portion into the environment and a slitthrough the protuberance and catheter body. The interior surface definesa generally concave interior wall portion opposite the convex exteriorsurface portion.

[0008] In another aspect, the invention features a slit valve catheterwith an elongated, generally tubular catheter body having an exteriorsurface exposed to an environment and an interior surface defining alumen. The catheter further includes a valve with a generally concaveexterior surface portion and a protuberance projecting radially inwardfrom the interior surface opposite the concave exterior surface portionand a slit through the protuberance and catheter body and having agenerally uniform wall thickness between the interior and exteriorsurface in portions adjacent the protuberance.

[0009] In another aspect, the invention features a slit valve catheter,having an elongated, generally tubular catheter body with an exteriorsurface exposed to an environment and an interior surface defining alumen. The catheter further includes a first valve and a second valve.The first valve includes a protuberance projecting radially from thecatheter body and a slit through the protuberance and catheter body.

[0010] In another aspect, the invention features a slit valve catheterwith an elongated, generally tubular catheter body having an exteriorsurface exposed to an environment and an interior surface defining afirst lumen and a second lumen. The catheter further includes a firstvalve to the first lumen which has a protuberance projecting radiallyfrom the catheter body and a slit through the protuberance and catheterbody to the first lumen.

[0011] In another aspect, the invention features infusing fluid into abody or aspirating fluid from a body by delivering into the body acatheter having a generally elongated catheter body including anexterior surface exposed to the body and an interior surface defining alumen. The catheter further includes an aspiration valve and an infusionvalve, where at least one of the valves includes a protuberanceprojecting from the catheter body for permitting one of aspiration orinfusion while resisting one of infusion or aspiration. The pressure inthe lumen is varied to effect infusion or aspiration.

[0012] Embodiments may include one or more of the following features.The protuberance has a radial projection no greater than the outerdiameter of the catheter body. The protuberance has a width no greaterthan twice a thickness of the catheter body measured between theexterior surface and the interior surface at a region adjacent theprotuberance. The protuberance has a geometrical inflection near itspoint of maximum projection. (A geometrical inflection is the regionwhere the curvature of the catheter (viewed in cross-section) changesfrom concave to convex or conversely, or the region in which the slopeof a line tangent to the curvature is zero and the slope of linesadjacent the region have different signs.) The protuberance has a pairof inflections near the circumferential boundary of the protuberance.The protuberance is generally hemispherical. The protuberance is anintegral extension of the catheter body. The protuberance extendsaxially no further than the valve. The protuberance extends axiallysubstantially the length of the catheter body. The valve is on asidewall of the catheter. The valve is on a forward-facing distal tip ofthe catheter.

[0013] Embodiments may also include one or more of the following. Thevalve includes a region having a convex exterior surface portion and theprotuberance projects outwardly from the convex portion into theenvironment. The valve includes a region having a convex exteriorsurface portion and the protuberance projects inwardly from an interiorsurface portion opposite the convex surface portion. The valve includesa region having a concave exterior surface portion and the protuberanceprojects outwardly from the portion into the environment. The valveincludes a region having a concave exterior surface portion and theprotuberance projects inwardly from an interior surface portion oppositethe concave exterior surface portion. The valve includes a region havinga generally flat exterior surface portion and the protuberance projectsoutwardly from the flat exterior surface portion. The valve includes aregion having a generally flat exterior surface portion and theprotuberance projects inwardly from an interior surface portion oppositethe flat exterior surface portion. The interior surface portion isgenerally flat. The catheter includes a first protuberance projectingfrom the exterior surface and a second protuberance projecting from theinterior surface portion generally opposite the first protuberance. Theradial projection of the first protuberance is different than the radialprojection of the second protuberance.

[0014] Embodiments may also include one or more of the following. Theinterior surface is generally circular in cross-section. The exteriorsurface is generally circular in cross-section. The catheter has agenerally uniform wall thickness between the interior and exteriorsurface in portions adjacent the protuberance.

[0015] Embodiments may also include one or more of the following. Thecatheter has a second valve and the second valve has a protuberanceprojecting radially from the catheter body and a slit through theprotuberance and catheter body. The protuberance on the first valveprojects from the exterior surface of the catheter into the environmentand the protuberance on the second valve projects from the interiorsurface of the catheter body into the lumen. The first valve is proximalof the second valve. The second valve is on a forward-facing distal tipof the catheter. The slit catheter has a second valve to the firstlumen. The catheter has a third valve to a second lumen.

[0016] Embodiments may also include one or more of the following. Bothan aspiration and infusion valve are in communication with the samelumen and each include a protuberance. The protuberance on theaspiration valve being arranged to resist infusion and the protuberanceon the infusion valve is arranged to resist aspiration. Alternatelyinfusion and aspirating fluid from the body by increasing and deliveringpressure in the lumen. The catheter may be delivered into the body overa guidewire.

[0017] Implementations may provide one or more advantages. For example,the protuberance may reduce leaks through the valve, especially leaksdue to unintended valve openings when pressure conditions in the lumenare opposite to the intended valve operation direction. The protuberancecan also control the level of lumen pressure needed to open the valve.The protuberance valves may be used on very thin-walled catheters inwhich the wall thickness is not sufficient to create an effective seal.A thinner catheter wall can provide a larger lumen, which may permitgreater infusion and aspiration flow rates without substantiallyincreasing the overall catheter diameter or the pressure differentialneeded to operate the valve.

[0018] Further aspects, features, and advantages follow.

DESCRIPTION OF THE PREFERRED EMBODIMENT(s)

[0019] We first briefly describe the drawings.

[0020] Drawings

[0021]FIG. 1 is a side view, in partial cross-section, of a catheter ina vessel;

[0022]FIG. 2 is an end-on cross-section of a pair of valves as theywould appear when viewed along the line 22 in FIG. 1, with the valves ina condition where neither infusion, nor aspiration is taking place;

[0023]FIG. 3 is a similar end-on cross-section of the valves in FIG. 2during infusion;

[0024]FIG. 4 is a similar end-on cross-section of the valves in FIG. 2,during aspiration;

[0025]FIG. 5 is a longitudinal cross-section in the valve regions inFIG. 1;

[0026]Fig. 6 is an end-on cross-section of another embodiment with apair of valves as they would appear when viewed along the line 22 inFIG. 1, with the valves in a condition where neither infusion noraspiration is taking place;

[0027]FIG. 7 is a similar end-on cross-section of the embodiment in FIG.6, during infusion;

[0028]FIG. 8 is a similar end-on cross-section of the embodiment of FIG.6 during aspiration;

[0029]FIG. 9 is an end-on cross-section of another embodiment with apair of valves as they would appear when viewed along the line 22 inFIG. 1, in a condition where neither infusion, nor aspiration is takingplace;

[0030]FIG. 10 is an end-on cross-section of another embodiment with apair of valves as they would appear when viewed along the line aa inFIG. 1, in a condition where neither infusion, nor aspiration is takingplace;

[0031]FIG. 11 is an end-on cross-section of another embodiment with apair of valves as they would appear when viewed along the line 22 FIG.1, in a condition where neither infusion, nor aspiration is takingplace.

[0032]FIG. 12 is a side view in partial cross-section of anotherembodiment;

[0033]FIG. 13a is an end-on cross-section along the line 13 a 13 a andFIG. 13b is an end-on cross-section along line 13 b 13 b in FIG. 12,with the valves in a condition where neither infusion, nor aspiration istaking place.

[0034]FIGS. 14 and 14a are longitudinal cross sections of anotherembodiment.

DESCRIPTION

[0035] Referring to FIG. 1, a catheter 2 is placed beneath the skin 4into, for example, a vessel 6 for either infusing fluid such as drug,nutrient, blood or other body fluid, into the body, or aspirating fluidfrom the body. The catheter includes an elongated polymeric member 7which has an outer surface 8 exposed to the body environment and aninner surface 9 defining a lumen 10 which extends substantially thelength of the catheter. The lumen is closed at the distal end 12 of thecatheter and can be accessed at the proximal end 13 through a fitting14, for example, a standard luer lock, which is connected to a syringe16 or another suitable device for injecting or withdrawing fluid fromthe lumen 10.

[0036] The insertion portion of the catheter has a pair of slit valveregions, including a first valve region 18 and a second valve region 20,which permit fluid communication between the body environment and thelumen 10 by varying the pressure in the lumen, P_(L) relative to thepressure in the body environment, P_(E).

[0037] Referring to FIGS. 2-4, one embodiment of a pair of valves, whichare located in the valve regions 18, 20, is illustrated in a series ofend-on cross-sectional views. In this case, the catheter cross-sectionis circular. In FIG. 2, the valve regions are shown in the condition inwhich the valves are sealed, for example, when the lumen pressure PL isessentially equal to the environmental pressure P_(E). The first valveregion 18 is used only for aspiration. The second valve region 20 isused only for infusion. Valve region 18 includes a slit 24 and valveregion 26 includes a slit 28.

[0038] The valves also include protuberances 22, 26 which project fromthe catheter body. In this case, both valves have the same generallyconvex outer catheter walls, with the protuberances arranged to make thevalves function as one-way valves in opposite directions; one one-wayvalve is for aspiration only and the other is for infusion only. Thefirst valve region 18 has a generally convex outer wall surface with aprotuberance 22 projecting from the inner wall surface into the lumen 10of the catheter. Slit 24 extends through protuberance 22. The secondvalve region also has a generally convex outer wall surface but with aprotuberance 26 projecting outward. Slit 28 also extends throughprotuberance 26.

[0039] Referring to FIG. 3, for infusion, the pressure in the lumen isincreased, for example, by depressing the plunger 17 of the syringe 16(FIG. 1), which creates the condition that the lumen pressure PL isgreater than the environment pressure P_(E). The increased lumenpressure acts upon the inwardly projecting protuberance 22 to create agreater sealing force (arrows 23) than in the absence of theprotuberance. The secure seal prevents any uncontrolled infusion throughthe first valve region. In the second valve region 20, the increasedlumen pressure creates a force (arrows 23′) that causes the catheterwall to flex outwardly along a flexure region spaced from the slit; theprotuberance 26 does not substantially inhibit opening of the slitvalve, permitting a controlled infusion to take place.

[0040] Referring to FIG. 4, for aspiration, the pressure within thelumen is reduced by, for example, withdrawing the plunger 17 of thesyringe 16 (FIG. 1). In the first valve region 18, the reduced pressurecauses the catheter wall to flex inwardly along flexure regions 31; theprotuberance 22 does not substantially interfere with the inward flexingof the valve, permitting controlled aspiration of fluid through thefirst valve. In the second valve region 20 the protuberance 26 resistsinversion or collapse, preventing uncontrolled aspiration through thesecond valve.

[0041] The protuberances assist valve operation by projecting into theenvironment or lumen. For example, projection of the protuberance into alumen increases sealing forces on the slit when the pressure in thelumen is increased because the protuberance modifies the contour aboutthe slit such that the components of pressure vectors perpendicular tothe slit are larger. The protuberances illustrated in the embodimentabove are generally hemispherical with geometrical inflections 25, 25′at the location of greatest projection and further geometricalinflections 27, 27′ and 29, 29′ near or at the boundaries of theprotuberance, where projection from the catheter body begins. Referringto FIG. 5, these protuberances also have short axial projections, whichextend only within the valve regions and generally correspond to thelength of the slit.

[0042] The shape and dimensions of the protuberance may be modified. Thewidth of the protuberance is preferably about twice the thickness of thecatheter body adjacent the protuberance or less. The projection of aprotuberance into a lumen is preferably equal to or less than the lumendiameter. The protuberance may project across substantially the entirewidth of a lumen. The projection from the outer surface of a catheter ispreferably equal to or less than the outer diameter of the catheter. Theprotuberance may project from a catheter body having an otherwiseuniform geometrical configuration, as indicated above, or theprotuberance may project from a catheter body having an irregular orcontoured inner and/or outer wall surface. The inflection points oneither side of the protuberance are preferably spaced from the flexureor hinge region of the valve. The protuberance may also be asymmetricalin cross-section and may not have inflections at its boundaries, butinstead extend smoothly from the otherwise uniform thickness and profileof the catheter wall. The protuberance may be oblong in shape.

[0043] One advantage is that the catheter may be operated at higherlumen pressures during infusion without inversion of the first valvewhich could lead to leaks or uncontrolled infusion. Similarly, theoutwardly extending protuberance in the second valve region enhancessealing during aspiration through the first valve. Higher vacuum can beused during aspiration without inversion of the second valve.Alternatively, the catheter can be arranged for operation at lowerpressure differentials for both infusion and aspiration. For example,the entire catheter body can be made of somewhat weak, thin-walledconstruction. The protuberance in the second valve region preventscollapse of the second valve during aspiration. During infusion throughthe second valve, the protuberance of the first valve prevents outwardinversion. A protuberance can be used to make a one-way valve from avalve that would ordinarily operate for both infusion and aspiration.For example, the valve wall may be weakened by chemical treatment or byreducing the thickness of the polymer, which would ordinarily encouragevalve action in either direction. However, a protuberance may be used toprevent valve action in one direction.

[0044] Manufacture

[0045] The catheters may be manufactured by injection molding or bymodifying an extruded tube. For example, extrusion may be used toprovide a uniform polymeric tube, to which a hub is attached at one endand the other end is sealed. Insert molding can then be used to providethe desired geometry of the slit regions. The slits could then becreated in the desired valve locations as a subsequent mechanicaloperation. Insert molding allows the tip to be formed of a materialeither identical to or dissimilar from the catheter tube. The moldeddetails in the protuberances include axial cross sectional geometry,protuberance longitudinal cross sectional geometry, protuberance length,wall thickness, degree of concave/convex curvature, etc. Othermanufacturing techniques include melting or otherwise adhering thecatheter portions as components or post-forming an extruded tube.

[0046] In particular embodiments, the polymer may be polyurethane,silicones, polyethylenes, nylons, polyesters and polyester elastomers.In one example, the catheter is polyurethane (e.g., Tecoflex, availablefrom Thermedics, Woburn, Mass.). The overall OD of the catheter is about3-16 French. The overall length of the catheter is about 20-60 cm. Forexample, a 5 French catheter may have a substantially constant catheterbody wall thickness, T, (FIG. 2) of about-0.015 inch and lumen diameterof about 0.035 inch. Protuberances are hemispherical, have a radialprojection, P, (FIG. 2) of about 0.015 inch, a longitudinal extension,E, (FIG. 5) of about 0.200 inch and a width, W, between boundaryinflection points (FIG. 2) of about 0.030 inch. The slit is formed by acutting device, such as a razor and has a length of 0.200 inch,substantially the same as the longitudinal projection of theprotuberance.

[0047] Additional Embodiments

[0048] Referring to FIGS. 6-8, another embodiment of a two-valvecatheter is illustrated. In this case, the first valve region 18 is usedfor aspiration. It includes an outer wall surface that is generallyconcave and a slit in the wall of the concave region. As known in theart, the concave surface assists opening of the slit by inward flexingof the catheter wall when a low pressure condition exists in the lumen,thus facilitating aspiration. The second valve region 20 has a generallyconvex outer surface. As known in the art, the convex surface assistsopening of the slit by outward flexing of the catheter wall whenpressure is increased in the catheter lumen, which facilitates infusion.

[0049] Both valve regions include a protuberance in the region of theslit. In the first valve region, a protuberance 42 projects into thelumen. In the second valve region, a protuberance 44 projects radiallyoutward into the environment. Slit 43 extends through protuberance 42and slit 45 extends through protuberance 44.

[0050] During infusion, the inwardly projecting protuberance 42 enhancessealing of the first valve region (FIG. 7) when lumen pressure isincreased to open the second valve region. During aspiration, fluid isaspirated through the first valve region (FIG. 8), without interferencefrom the protuberance 42, while sealing is enhanced at the second valveregion by the outward projecting protuberance 44. The protuberance 42 onthe infusion valve prevents inversion at the somewhat higher pressuredifferentials needed for operation of an aspiration valve with a convexouter surface.

[0051] In another embodiment, both valve regions have concave outersurfaces, with the first valve having an inwardly projectingprotuberance and the second valve having an outwardly projectingprotuberance. The first valve is used for aspiration and the secondvalve is used for infusion.

[0052] Referring to FIG. 9, in another embodiment, both the first andsecond valve regions include outwardly projecting protuberances and theprotuberances project different amounts. The first valve regionprotuberance 52, projects less than the second valve region protuberance54. The valves are shown in a neutral pressure condition. Foraspiration, a controlled lumen pressure causes the first valve region toinvert while the larger protuberance 54 in the second valve regionprevents inversion. For infusion, an increase in pressure causes bothfirst and second valve regions to open.

[0053] Referring to FIG. 10, in another embodiment, the first valveregion includes an outwardly projecting protuberance 62 while the secondvalve region includes both an outwardly projecting protuberance 64 andan inwardly projecting protuberance 66. The protuberance 66 projects toa lesser extent than the protuberance 64. The catheter is shown in acondition where neither infusion, nor aspiration is taking place. Duringinfusion, the first valve opens first, at low initial pressure whileinward projection 66 keeps the second valve sealed. At higher pressure,the sealing effect, of the inward projection 66 is overcome and infusionoccurs through both of the values. Preferably, this embodiment is usedfor infusion only. In an alternate embodiment, both valves could bearranged for aspiration only, by forming both first and second regionswith concave exterior surfaces.

[0054] Referring to FIG. 11, another embodiment has a first valve regionthat includes a flat surface 70 with an outwardly projectingprotuberance 72 and the second valve region also includes a flat region74 without any protuberance. During aspiration, the protuberance 72prevents opening of the first valve while aspiration occurs through thesecond valve. Infusion may occur through both the first and secondvalves.

[0055] Referring to FIGS. 12-13 b, in another embodiment, a multilumencatheter is provided with multiple valve regions. Referring particularlyto FIG. 12, the catheter 80 includes a catheter body 82 with an exteriorsurface 84 and an interior surface 86 between which the outer catheterwall thickness is defined. The interior surface, and an inner lumen wall87, define a first lumen 88 and a second lumen 90. Both lumens 88, 90are closed at the distal end 92 of the catheter and can be accessedthrough a luer coupling 94 at the proximal end of the catheter. Thelumen 88 is in fluid communication with the environment through a firstvalve region 96 and a second valve region 100. The lumen 90 is incommunication with the environment through a valve region 98.

[0056] Referring particularly to FIG. 13a, an end on cross sectionillustrates the valve regions 96, 98. Region 98 includes a generallyconvex outer wall surface geometry and an outwardly projectingprotuberance 102, and a slit 97 extending through the wall andprotuberance 102. The region 96 includes a generally concave outer wallsurface geometry and an inwardly projecting protuberance 103 and a slit99 extending through the wall and protuberance 103.

[0057] Referring to FIG. 13b, an end on cross section illustrates thevalve region 100, which includes a generally convex catheter geometryand a slit 101 extending through the body. The region 96 also includesan outwardly projecting protuberance 104.

[0058] In operation, infusion can be carried out by increasing thepressure in the lumens 88 and 90, which causes the valves at regions 98,100 to open and the valve at region 96 to seal tightly. For aspiration,pressure in lumen 88 is reduced which causes the valve at region 96 toopen while the valve at region 100 seals tightly. Alternatively, orsimultaneously, with infusion or aspiration as above, infusion can occurby increasing the pressure in lumen 88 to open the valve at region 100.Further multi-lumen catheter embodiments include catheters in which oneor both of the lumens have a valve arrangement as described in FIGS.1-11.

[0059] Referring to FIG. 14, in another embodiment, at least one slitvalve 105 is provided at the forward-facing distal tip of the catheter.In this example, the tip has a generally convex, hemispherical outersurface 106 and a protuberance 108 extending outwardly from the catheterand including a slit 110 for use as an infusion valve. (Alternatively,the tip of the catheter may be concave for use as an aspiration valve.)Referring particularly to FIG. 14a, a catheter with a slit valve at thetip may make delivery over a guidewire 112 easier. The guidewire mayextend through the valve 105 into the lumen 114. As illustrated, theguidewire may exit the lumen through a slit region 116 on the catheterwall to facilitate rapid exchange of the guidewire. (Alternatively, theguidewire 112 may extend through the lumen to the proximal hub. Theguidewire could also be passed through a valve on the side wall of thecatheter, without passing through the valve at the tip.) The cathetermay include additional valves, such as a slit valve 118 for infusion.The tip of the catheter may be manufactured as a separate componentwhich is glued or molded, at attachment point 120, to the rest of thecatheter body. In use, the catheter may be slid over the guidewire intoa vessel. Infusion or aspiration may be conducted while the guidewireextends through the valve. Alternatively, the guidewire can be withdrawnfrom the valve prior to infusion or aspiration.

[0060] In additional embodiments, the catheter and valve types can beused in various combinations to create various combinations of infusionand aspiration effects using the principles illustrated above. Aprotuberance could be used on a catheter with a single slit valve. Theprotuberance may be trimmed manually by the physician prior to placementin the body to select the pressure differential needed to operate thevalve. The protuberance could continue a distance along the catheter,for example, substantially the length of the catheter. The catheters canbe sized for use in various parts of the body. A valve may have multipleintersecting slits. Multiple valves may be offset radially. In catheterswith multiple valves, an infusion valve may be positioned proximal of anaspiration valve, for, e.g., flushing the downstream exterior of thecatheter including the aspiration valve area with Urokinase to dissolvefibrin deposits. Alternatively, an infusion valve may be positioneddistal of the aspiration valve, preferably near the distal end of thecatheter, to facilitate flushing the full length of the lumen andavoiding dead volume. The catheters can be used in the vascular systemfor central venous access, to deliver, for example, drugs to a cancerpatient. The catheter can be placed by a cutdown or the Seldingertechnique.

[0061] Still further embodiments are within the following claims.

What is claimed is:
 1. A slit valve catheter, comprising: an elongated,generally tubular catheter body having an exterior surface exposed to anenvironment and an interior surface defining a lumen, said catheterfurther including a valve which has a protuberance projecting from thecatheter body and a slit through the protuberance and catheter body. 2.The catheter of claim 1 wherein said protuberance projects from theexterior surface of the catheter body into the environment.
 3. Thecatheter of claim 1 wherein said protuberance projects from the interiorsurface into the lumen.
 4. The catheter of claim 1 wherein theprotuberance has a radial projection no greater than the outer diameterof the catheter body.
 5. The catheter of claim 1 wherein theprotuberance has a width no greater than twice a thickness of thecatheter body measured between the exterior surface and the interiorsurface at a region adjacent the protuberance.
 6. The catheter of claim1 wherein the protuberance has a geometrical inflection near its pointof maximum projection.
 7. The catheter of claim 1 or 6 wherein theprotuberance has a pair of inflections near the circumferential boundaryof the protuberance.
 8. The catheter of claim 1 wherein the protuberanceis generally hemispherical.
 9. The catheter of claim 1 wherein theprotuberance is an integral extension of said catheter body.
 10. Thecatheter of claim 1 wherein the protuberance extends axially no furtherthan the valve.
 11. The catheter of claim 1 wherein the protuberanceextends axially substantially the length of said catheter body.
 12. Thecatheter of claim 1 wherein the valve is on a sidewall of the catheter.13. The catheter of claim 1 wherein the valve is on a forward-facingdistal tip of the catheter.
 14. The catheter of claim 1 wherein saidvalve includes a region having a convex exterior surface portion andsaid protuberance projects outwardly from said convex portion into theenvironment.
 15. The catheter of claim 1 wherein said valve includes aregion having a convex exterior surface portion and said protuberanceprojects inwardly from an interior surface portion opposite said convexsurface portion.
 16. The catheter of claim 1 wherein said valve includesa region having a concave exterior surface portion and said protuberanceprojects outwardly from said portion into the environment.
 17. Thecatheter of claim 1 wherein said valve includes a region having aconcave exterior surface portion and said protuberance projects inwardlyfrom an interior surface portion opposite said concave exterior surfaceportion.
 18. The catheter of claim 1 wherein said valve includes aregion having a generally flat exterior surface portion and saidprotuberance projects outwardly from said flat exterior surface portion.19. The catheter of claim 1 wherein said valve includes a region havinga generally flat exterior surface portion and said protuberance projectsinwardly from an interior surface portion opposite said flat exteriorsurface portion.
 20. The catheter of claim 18 or 19 wherein saidinterior surface portion is generally flat.
 21. The catheter of claim 1wherein said catheter includes a first protuberance projecting from theexterior surface and a second protuberance projecting from the interiorsurface portion generally opposite said first protuberance.
 22. Thecatheter of claim 21 wherein the amount of projection of the firstprotuberance is different than the amount of projection of the secondprotuberance. 23.A slit valve catheter, comprising: an elongated,generally tubular catheter body having an exterior surface exposed to anenvironment and an interior surface defining a lumen, said catheterfurther including a valve with a generally convex exterior surfaceportion and a protuberance projecting radially outward from the convexexterior surface portion into the environment and a slit through theprotuberance and catheter body, the interior surface defining agenerally concave interior surface portion opposite the convex exteriorsurface portion.
 24. The catheter of claim 23 wherein said interiorsurface is generally circular in cross-section.
 25. The catheter ofclaim 24 wherein said exterior surface is generally circular incross-section.
 26. The catheter of claim 25 wherein the catheter has agenerally uniform wall thickness between said interior and exteriorsurface in portions adjacent said protuberance.
 27. The catheter ofclaim 26 wherein said protuberance is generally hemispherical.
 28. Aslit valve catheter, comprising: an elongated, generally tubularcatheter body having an exterior surface exposed to an environment andan interior surface defining a lumen, said catheter further includes avalve with a generally concave exterior surface portion and aprotuberance projecting radially inward from the interior surfaceopposite the concave exterior surface portion and a slit through theprotuberance and catheter body, and having a generally uniform wallthickness between the interior and exterior surface in portions adjacentsaid protuberance.
 29. The catheter of claim 28 wherein saidprotuberance is generally hemispherical.
 30. A slit valve catheter,comprising an elongated, generally tubular catheter body having anexterior surface exposed to an environment and an interior surfacedefining a lumen, said catheter further including a first valve and asecond valve, said first valve including a protuberance projectingradially from the catheter body and a slit through the protuberance andcatheter body.
 31. The catheter of claim 30 wherein said protuberanceprojects from the exterior surface of catheter body into theenvironment.
 32. The catheter of claim 30 wherein said protuberanceprojects from the interior surface into the lumen.
 33. The catheter ofclaim 30 wherein the second valve has a protuberance projecting radiallyfrom the catheter body and a slit through the protuberance and catheterbody.
 34. The catheter of claim 33 wherein the protuberance on the firstvalve projects from the exterior surface of the catheter into theenvironment and the protuberance on the second valve projects from theinterior surface of the catheter body into the lumen.
 35. The catheterof claim 34 wherein the first valve is proximal of the second valve. 36.The catheter of claim 34 wherein the first valve is distal of the secondvalve.
 37. The catheter of claim 34 wherein said second valve is on aforward-facing distal tip of the catheter.
 38. The catheter of claim 29wherein said protuberance is generally hemispherical.
 39. A slit valvecatheter, comprising an elongated, generally tubular catheter bodyhaving an exterior surface exposed to an environment and an interiorsurface defining a first lumen and a second lumen, said catheter furtherincluding a first valve to said first lumen which has a protuberanceprojecting radially from the catheter body and a slit through theprotuberance and catheter body to said first lumen.
 40. The slit valvecatheter of claim 39 comprising a second valve to said first lumen. 41.The slit valve catheter of claim 40 comprising a third valve to saidsecond lumen.
 42. A method of infusing fluid into a body or aspiratingfluid from a body comprising: delivering into the body a catheter havinga generally elongated catheter body including an exterior surfaceexposed to the body and an interior surface defining a lumen, thecatheter further including an aspiration valve and an infusion valve,wherein at least one of said valves includes a protuberance projectingfrom the catheter body for permitting one of aspiration or infusionwhile resisting one of infusion or aspiration, and varying pressure insaid lumen to effect infusion or aspiration.
 43. The method of claim 42wherein both said aspiration and infusion valve are in communicationwith the same lumen and each include a protuberance, said protuberanceon said aspiration valve being arranged to resist infusion and saidprotuberance on said infusion valve being arranged to resist aspiration,and alternately infusion and aspirating fluid from said body byincreasing and delivering pressure in said lumen.
 44. The method ofclaim 43 comprising delivering said catheter into the body over aguidewire.